Two-Terminal Ferroelectric Memory with Extended Drain for Multi-Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ferroelectric memory devices, particularly the capacitor and FET types, face challenges in implementing multi-resistance levels and synaptic applications due to destructive read properties, complex integration, and three-terminal operations, which hinder their application in neuromorphic technologies.
Innovation Solution
A two-terminal memory device with a ferroelectric layer made of materials like PVDF or HfZrO2, where the extended drain overlaps the ferroelectric layer, allowing for voltage-controlled polarization adjustments and linear conductance changes, enabling multi-layer switchable resistance layers and simplifying the structure for cross-point array integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a capacitor type ferroelectric memory is used, then information retention property is improved, but destructive read property and requirement for rewrite process worsen the operation complexity
Solution Approach 1:
The patent inverts the conventional capacitor-type ferroelectric memory structure by using a transistor-type configuration where the ferroelectric layer serves as the gate dielectric. This inversion allows non-destructive read operations while maintaining information retention, as the polarization state can be sensed without being destroyed.
Solution Approach 2:
The ferroelectric layer in the transistor-type structure serves multiple functions: it acts as the gate dielectric for voltage control, stores information through polarization states, and enables both read and write operations without requiring separate capacitor structures, thereby simplifying the overall device architecture.
2Ease of operation
If an FET type ferroelectric memory is used, then non-destructive read operation is improved, but three-terminal operation increases device complexity
Solution Approach 1:
The patent extracts the gate terminal function from the conventional three-terminal FET structure and integrates it with the drain terminal. The extended drain electrode serves both as the drain for current flow and as the gate for voltage control, thereby reducing the device to two terminals while maintaining non-destructive read capability.
Solution Approach 2:
The patent merges the gate and drain functions into a single extended drain electrode structure. This combined electrode applies voltage to control the channel conductivity while simultaneously serving as the current output terminal, thereby eliminating the need for a separate gate terminal and reducing device complexity.
3Reliability
If conventional ferroelectric materials are used, then polarization property is improved, but manufacturing cost and processing difficulty increase
Solution Approach 1:
The patent changes the material parameter from conventional ferroelectric materials (such as PZT or PBMT) to organic ferroelectric materials (such as PVDF or P(VDF-TrFE)). This material substitution maintains the necessary polarization properties while significantly reducing manufacturing cost and simplifying processing, as organic materials can be deposited at lower temperatures and with simpler techniques.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The two-terminal ferroelectric synaptic device improves integration, reduces complexity, and enables efficient read, write, and erase operations without a gate, making it suitable for neuromorphic applications and reducing power consumption.
Implementation Method 1
a ferroelectric layer connected to the source and the drain and formed between the source and the drain
Implementation Method 2
where the extended drain overlaps the ferroelectric layer, allowing for voltage-controlled polarization adjustments and linear conductance changes
Data Source
AI summary
A two-terminal memory device including: a substrate; a source and a drain formed to face each other on an upper surface of the substrate; a ferroelectric layer connected to the source and the drain and formed between the source and the drain; and an extended drain extending from the drain and laminated on the ferroelectric layer. The two-terminal memory device may be applied as a cross-point type and neuromorphic device capable of implementing multi-resistance levels with multi-layer switchable resistance layers.